Tomato Focaccia

In the States, we tend to be familiar only with the bready, crisp-topped version of focaccia­, but this Pugliese take on ittowering, savory, and so light it's almost cakelikewill surely become a new favorite. Food editor Gina Marie Miraglia Eriquez learned the secret to a springy, rich varietya potato mashed into the doughfrom her husband's cousin Lucia Erriquez (yes, with two r's) Castellana, who comes from Bari. A salty top and tangy tomatoes that go almost buttery on the crust will have everyone reaching for a second piece.

Preparation

Generously cover potato with salted cold water (1 teaspoon salt for 3 cups water) in a small heavy saucepan and simmer, uncovered, until just tender, 10 to 15 minutes. Drain and cool slightly, then mash until smooth.

Stir together warm water and sugar in bowl of mixer. Sprinkle yeast over mixture and let stand until foamy, about 5 minutes.
(If mixture doesn't foam, start over with new yeast.)

Add potato and 1/4 cup oil to yeast and beat with paddle attachment at medium speed until combined, about 2 minutes. Remove paddle attachment and attach dough hook, then beat in 4 cups flour and 1 tablespoon sea salt at medium-high speed until combined well, about 3 minutes. (Dough will be very soft and sticky.)

Transfer to a well-floured surface and knead in remaining 1/4 cup flour with lightly floured hands until smooth and elastic, 8 to 10 minutes. (Dough will still be very soft and sticky.)

Scrape dough into a lightly oiled large bowl and cover bowl with oiled plastic wrap. Let dough rise in a draft-free place at warm room temperature until doubled, 2 to 2 1/2 hours. Generously oil a 15- by 10- by 1-inch baking pan.

Punch down dough (do not knead) and transfer to baking pan, then gently stretch to cover as much of bottom as possible (dough may not fit exactly).

Cover dough with oiled plastic wrap and a kitchen towel and let rise in a draft-free place at warm room temperature until doubled, 1 to 1 1/2 hours.

Bake until center is firm, top is pale golden, and underside is golden (lift to check), 20 to 25 minutes.

Loosen focaccia from pan with a spatula and slide onto a rack to cool slightly. Cut into pieces and serve warm or at room temperature.

Cooks' note:
Focaccia is best eaten the day it is made but can be baked 1 day ahead and kept, wrapped in foil, in a sealed bag at room temperature. If desired, reheat, uncovered, in a 350°F oven until just heated through, about 10 minutes.